ExpressExtension Support

When is the due date to file Form 1120?

Generally, all domestic corporations (excluding Forms 1120-S and 1120-C) must file Form 1120 by the 15th day of the 4th month after the end of their tax year. This applies to:

• Corporations following the calendar tax year (April 15, 2025)

• Corporations with a fiscal year ending on any month except June 30

• New corporations filing a short-period return

• Corporations that have dissolved and are filing a final return

Exceptions:

• S corporations, partnerships, and all C corporations with a fiscal tax year ending June 30 must file by the 15th day of the 3rd month after the end of their tax year. 

• Additionally, corporations with a short tax year ending in June must file by the 15th day of the 3rd month after the end of their tax year.